1. Field of the Invention
The present invention generally relates to a linear equalizer.
2. Description of Related Art
A linear equalizer receives an input signal and outputs an output signal, wherein a first frequency component of the input signal is suppressed while a second frequency component of the input signal is enhanced. Usually, a lower frequency component is suppressed while a higher frequency component is enhanced. This effectively corrects a frequency dispersion of the input signal that often exists in many practical applications. A linear equalizer can be embodied using a FIR (finite impulse response) filter. In U.S. Pat. No. 8,255,449, Lin et al taught a continuous-time FIR filter that can be used as a linear equalizer. A drawback of the continuous-time FIR filter is that the overall circuit speed is reduced when the order of the filter is increased. This limits the order of the filter that can be practically implemented. The same drawback applies to any type of continuous-time filter.
What is desired is a linear equalizer that allows an increase of an order of filtering without materially reducing the overall circuit bandwidth.